How to Change Harley Oil: The Three-Hole Service

A Big Twin has three separate oil compartments: engine, primary and transmission. A full service changes all three. Sportsters share one oil between the primary and gearbox, so they need two.

What oil does a Harley take?

Most air-cooled Harley V-twins run a 20W-50 motorcycle oil in the engine. Primary and transmission oils are often different products, so check your owner’s manual. The Harley oil filter size also varies: Twin Cam and Milwaukee-Eight engines use spin-on filters, but lengths differ between models.

Steps

1. Ride for 10 minutes to warm the oil, then park on level ground.
2. Drain the engine oil and remove the filter.
3. Wipe a film of clean oil on the new filter seal and fit it hand-tight, then the extra turn your manual specifies.
4. Refill and check the level using the method in your manual (some models are checked warm and upright).
5. Drain and refill the primary and transmission with new O-rings on the drain plugs.

Our Harley oil change kit includes all three oils, the filter and O-rings.